1. Field of Invention
The present invention relates to a laser scanning device, and more particularly to a laser scanning device capable of compensating the aberration and the dispersion which are caused when the visible light beam passes through a scanning focusing unit.
2. Related Art
Laser processing technology is a method for scanning an object with a laser beam and generating a mark. In the industry, many types of lasers are used in processing, for example, carbon dioxide laser, semiconductor laser, and diode laser.
A production line of a conventional laser processing flow mainly is divided into three blocks, in which a first block is a positioning region, a second block is a processing region, and a third block is a detection region. However, before laser processing, the production line first performs a positioning process in the positioning region by using a charge couple device (CCD), then performs laser processing in the processing region, and finally performs a detection process in the detection region by using a CCD. The above-mentioned laser processing needs three CCDs and a laser scanning device, and thus the problems that many components are needed, a large space is occupied, and synchronous detection cannot be achieved exist.
Moreover, currently, the conventional laser scanning and detection devices on the market are all designed for the scanning of a central position, such that the images obtained at the central area are clear, while the images obtained at non-central areas are blurred. Further, when the scanning angle of the conventional laser scanning device with respect to a platform is not orthogonal (that is, an angle formed by the laser beam and an optical axis of a scanning mirror is not 45 degrees), as the wavelengths of the laser beam and the visible light beam are different, after the visible light beam passes through the scanning mirror, a dispersion is caused, and thus the position actually scanned by the laser beam is different from the scanning processing position where the CCD receives the visible light beam to obtain the image, so that the accuracy of the detection process is affected.